/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.scheduling.quartz;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.quartz.Calendar;
import org.quartz.JobDetail;
import org.quartz.JobListener;
import org.quartz.ListenerManager;
import org.quartz.ObjectAlreadyExistsException;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.SchedulerListener;
import org.quartz.Trigger;
import org.quartz.TriggerListener;
import org.quartz.spi.ClassLoadHelper;
import org.quartz.xml.XMLSchedulingDataProcessor;

import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.ResourceLoader;
import org.springframework.lang.Nullable;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionException;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.DefaultTransactionDefinition;

/**
 * Common base class for accessing a Quartz Scheduler, i.e. for registering jobs,
 * triggers and listeners on a {@link org.quartz.Scheduler} instance.
 *
 * <p>For concrete usage, check out the {@link SchedulerFactoryBean} and
 * {@link SchedulerAccessorBean} classes.
 *
 * <p>Compatible with Quartz 2.1.4 and higher, as of Spring 4.1.
 *
 * @author Juergen Hoeller
 * @author Stephane Nicoll
 * @since 2.5.6
 */
public abstract class SchedulerAccessor implements ResourceLoaderAware {

    protected final Log logger = LogFactory.getLog(getClass());
    @Nullable
    protected ResourceLoader resourceLoader;
    private boolean overwriteExistingJobs = false;
    @Nullable
    private String[] jobSchedulingDataLocations;
    @Nullable
    private List<JobDetail> jobDetails;
    @Nullable
    private Map<String, Calendar> calendars;
    @Nullable
    private List<Trigger> triggers;
    @Nullable
    private SchedulerListener[] schedulerListeners;
    @Nullable
    private JobListener[] globalJobListeners;
    @Nullable
    private TriggerListener[] globalTriggerListeners;
    @Nullable
    private PlatformTransactionManager transactionManager;

    /**
     * Set whether any jobs defined on this SchedulerFactoryBean should overwrite
     * existing job definitions. Default is "false", to not overwrite already
     * registered jobs that have been read in from a persistent job store.
     */
    public void setOverwriteExistingJobs(boolean overwriteExistingJobs) {
        this.overwriteExistingJobs = overwriteExistingJobs;
    }

    /**
     * Set the location of a Quartz job definition XML file that follows the
     * "job_scheduling_data_1_5" XSD or better. Can be specified to automatically
     * register jobs that are defined in such a file, possibly in addition
     * to jobs defined directly on this SchedulerFactoryBean.
     *
     * @see org.quartz.xml.XMLSchedulingDataProcessor
     */
    public void setJobSchedulingDataLocation(String jobSchedulingDataLocation) {
        this.jobSchedulingDataLocations = new String[]{jobSchedulingDataLocation};
    }

    /**
     * Set the locations of Quartz job definition XML files that follow the
     * "job_scheduling_data_1_5" XSD or better. Can be specified to automatically
     * register jobs that are defined in such files, possibly in addition
     * to jobs defined directly on this SchedulerFactoryBean.
     *
     * @see org.quartz.xml.XMLSchedulingDataProcessor
     */
    public void setJobSchedulingDataLocations(String... jobSchedulingDataLocations) {
        this.jobSchedulingDataLocations = jobSchedulingDataLocations;
    }

    /**
     * Register a list of JobDetail objects with the Scheduler that
     * this FactoryBean creates, to be referenced by Triggers.
     * <p>This is not necessary when a Trigger determines the JobDetail
     * itself: In this case, the JobDetail will be implicitly registered
     * in combination with the Trigger.
     *
     * @see #setTriggers
     * @see org.quartz.JobDetail
     */
    public void setJobDetails(JobDetail... jobDetails) {
        // Use modifiable ArrayList here, to allow for further adding of
        // JobDetail objects during autodetection of JobDetail-aware Triggers.
        this.jobDetails = new ArrayList<>(Arrays.asList(jobDetails));
    }

    /**
     * Register a list of Quartz Calendar objects with the Scheduler
     * that this FactoryBean creates, to be referenced by Triggers.
     *
     * @param calendars a Map with calendar names as keys as Calendar
     *                  objects as values
     * @see org.quartz.Calendar
     */
    public void setCalendars(Map<String, Calendar> calendars) {
        this.calendars = calendars;
    }

    /**
     * Register a list of Trigger objects with the Scheduler that
     * this FactoryBean creates.
     * <p>If the Trigger determines the corresponding JobDetail itself,
     * the job will be automatically registered with the Scheduler.
     * Else, the respective JobDetail needs to be registered via the
     * "jobDetails" property of this FactoryBean.
     *
     * @see #setJobDetails
     * @see org.quartz.JobDetail
     */
    public void setTriggers(Trigger... triggers) {
        this.triggers = Arrays.asList(triggers);
    }

    /**
     * Specify Quartz SchedulerListeners to be registered with the Scheduler.
     */
    public void setSchedulerListeners(SchedulerListener... schedulerListeners) {
        this.schedulerListeners = schedulerListeners;
    }

    /**
     * Specify global Quartz JobListeners to be registered with the Scheduler.
     * Such JobListeners will apply to all Jobs in the Scheduler.
     */
    public void setGlobalJobListeners(JobListener... globalJobListeners) {
        this.globalJobListeners = globalJobListeners;
    }

    /**
     * Specify global Quartz TriggerListeners to be registered with the Scheduler.
     * Such TriggerListeners will apply to all Triggers in the Scheduler.
     */
    public void setGlobalTriggerListeners(TriggerListener... globalTriggerListeners) {
        this.globalTriggerListeners = globalTriggerListeners;
    }

    /**
     * Set the transaction manager to be used for registering jobs and triggers
     * that are defined by this SchedulerFactoryBean. Default is none; setting
     * this only makes sense when specifying a DataSource for the Scheduler.
     */
    public void setTransactionManager(PlatformTransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }

    @Override
    public void setResourceLoader(ResourceLoader resourceLoader) {
        this.resourceLoader = resourceLoader;
    }


    /**
     * Register jobs and triggers (within a transaction, if possible).
     */
    protected void registerJobsAndTriggers() throws SchedulerException {
        TransactionStatus transactionStatus = null;
        if (this.transactionManager != null) {
            transactionStatus = this.transactionManager.getTransaction(new DefaultTransactionDefinition());
        }

        try {
            if (this.jobSchedulingDataLocations != null) {
                ClassLoadHelper clh = new ResourceLoaderClassLoadHelper(this.resourceLoader);
                clh.initialize();
                XMLSchedulingDataProcessor dataProcessor = new XMLSchedulingDataProcessor(clh);
                for (String location : this.jobSchedulingDataLocations) {
                    dataProcessor.processFileAndScheduleJobs(location, getScheduler());
                }
            }

            // Register JobDetails.
            if (this.jobDetails != null) {
                for (JobDetail jobDetail : this.jobDetails) {
                    addJobToScheduler(jobDetail);
                }
            }
            else {
                // Create empty list for easier checks when registering triggers.
                this.jobDetails = new LinkedList<>();
            }

            // Register Calendars.
            if (this.calendars != null) {
                for (String calendarName : this.calendars.keySet()) {
                    Calendar calendar = this.calendars.get(calendarName);
                    getScheduler().addCalendar(calendarName, calendar, true, true);
                }
            }

            // Register Triggers.
            if (this.triggers != null) {
                for (Trigger trigger : this.triggers) {
                    addTriggerToScheduler(trigger);
                }
            }
        }

        catch (Throwable ex) {
            if (transactionStatus != null) {
                try {
                    this.transactionManager.rollback(transactionStatus);
                }
                catch (TransactionException tex) {
                    logger.error("Job registration exception overridden by rollback exception", ex);
                    throw tex;
                }
            }
            if (ex instanceof SchedulerException) {
                throw (SchedulerException) ex;
            }
            if (ex instanceof Exception) {
                throw new SchedulerException("Registration of jobs and triggers failed: " + ex.getMessage(), ex);
            }
            throw new SchedulerException("Registration of jobs and triggers failed: " + ex.getMessage());
        }

        if (transactionStatus != null) {
            this.transactionManager.commit(transactionStatus);
        }
    }

    /**
     * Add the given job to the Scheduler, if it doesn't already exist.
     * Overwrites the job in any case if "overwriteExistingJobs" is set.
     *
     * @param jobDetail the job to add
     * @return {@code true} if the job was actually added,
     * {@code false} if it already existed before
     * @see #setOverwriteExistingJobs
     */
    private boolean addJobToScheduler(JobDetail jobDetail) throws SchedulerException {
        if (this.overwriteExistingJobs || getScheduler().getJobDetail(jobDetail.getKey()) == null) {
            getScheduler().addJob(jobDetail, true);
            return true;
        }
        else {
            return false;
        }
    }

    /**
     * Add the given trigger to the Scheduler, if it doesn't already exist.
     * Overwrites the trigger in any case if "overwriteExistingJobs" is set.
     *
     * @param trigger the trigger to add
     * @return {@code true} if the trigger was actually added,
     * {@code false} if it already existed before
     * @see #setOverwriteExistingJobs
     */
    private boolean addTriggerToScheduler(Trigger trigger) throws SchedulerException {
        boolean triggerExists = (getScheduler().getTrigger(trigger.getKey()) != null);
        if (triggerExists && !this.overwriteExistingJobs) {
            return false;
        }

        // Check if the Trigger is aware of an associated JobDetail.
        JobDetail jobDetail = (JobDetail) trigger.getJobDataMap().remove("jobDetail");
        if (triggerExists) {
            if (jobDetail != null && this.jobDetails != null &&
                    !this.jobDetails.contains(jobDetail) && addJobToScheduler(jobDetail)) {
                this.jobDetails.add(jobDetail);
            }
            try {
                getScheduler().rescheduleJob(trigger.getKey(), trigger);
            }
            catch (ObjectAlreadyExistsException ex) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Unexpectedly encountered existing trigger on rescheduling, assumably due to " +
                            "cluster race condition: " + ex.getMessage() + " - can safely be ignored");
                }
            }
        }
        else {
            try {
                if (jobDetail != null && this.jobDetails != null && !this.jobDetails.contains(jobDetail) &&
                        (this.overwriteExistingJobs || getScheduler().getJobDetail(jobDetail.getKey()) == null)) {
                    getScheduler().scheduleJob(jobDetail, trigger);
                    this.jobDetails.add(jobDetail);
                }
                else {
                    getScheduler().scheduleJob(trigger);
                }
            }
            catch (ObjectAlreadyExistsException ex) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Unexpectedly encountered existing trigger on job scheduling, assumably due to " +
                            "cluster race condition: " + ex.getMessage() + " - can safely be ignored");
                }
                if (this.overwriteExistingJobs) {
                    getScheduler().rescheduleJob(trigger.getKey(), trigger);
                }
            }
        }
        return true;
    }

    /**
     * Register all specified listeners with the Scheduler.
     */
    protected void registerListeners() throws SchedulerException {
        ListenerManager listenerManager = getScheduler().getListenerManager();
        if (this.schedulerListeners != null) {
            for (SchedulerListener listener : this.schedulerListeners) {
                listenerManager.addSchedulerListener(listener);
            }
        }
        if (this.globalJobListeners != null) {
            for (JobListener listener : this.globalJobListeners) {
                listenerManager.addJobListener(listener);
            }
        }
        if (this.globalTriggerListeners != null) {
            for (TriggerListener listener : this.globalTriggerListeners) {
                listenerManager.addTriggerListener(listener);
            }
        }
    }


    /**
     * Template method that determines the Scheduler to operate on.
     * To be implemented by subclasses.
     */
    protected abstract Scheduler getScheduler();

}
